The NHBS project was established to monitor selected behaviors and access to prevention services among groups at high risk for HIV infection. NHBS activities are being implemented in multiple cycles. Each cycle is referred to by the group of interest: men who have sex with men (MSM), injecting drug users (IDU), and heterosexuals at risk for HIV infection (HET). The NHBS objectives include: to conduct a minimum 500 NHBS surveys each year to assess the prevalence of and trends in risk behaviors; to conduct voluntary testing for HIV infection in order to assess HIV seroprevalence and incidence; to identify prevention strategies including HIV testing services for the targeted populations in the St. Louis Metropolitan Statistical Area (SLMSA); to collaborate on the NHBS survey development and implementation with the SLMSA community base organizations and Missouri academia or institutes; to conduct evaluations of the NHBS system, sampling strategies and data collection methods. For this project the Respondent Driven Sampling and Venue Based Sampling are the sampling methods. The NHBS survey is anonymous with no identifiers linking the participants to their responses. [unreadable] [unreadable] [unreadable]